Alloy roll-steel.



FRANK D. TAG-GART, OF WYOMISSING, PENNSYLVANIA.

ALLOY ROLL-STEEL.

No Drawing.

To all whom it may concern Be it known that I, FRANK D. TAGGART, acitizen of the United States, residing at \Vyomissing, in the county ofBerks and State of Pennsylvania, have invented certain new and usefulImprovements in Alloy Roll-Steel, of which the following is aspecification.-

My object is to provide an improved alloy steel adapted particularly forthe manufacture of rolls used in shaping steel bars and plates ofvarious sections.

Rolls having a moderate percentage of 1 carbon, as from .40 to 1.15, andalso of nickel in some cases, are frequently employed in the earlierrolling processes, while chill rolls are generally used in the finalfinishing processes; the former possessing the strength requisite forroughly reducing the ingots and billets or slabs to approximately thesectional form desired, while the latter possess the smooth hardenedsurface required for the finishing passes, though lacking in requisitestrength to withstand the shocks and strains incident to the roughingpasses, and also liable to develop objectionable and weakening surfacecracks.

My purpose is to provide a special alloy steel adapted for theproduction of rolls having all the requisite rolling qualities in highdegree, to wit: rigidity and strength to insure against both distortionand breakage under the shocks and strains incident to satisfactoryreduction in the passes; and homogeneity and surface hardness to insureagainst surface cracks and wear; the resulting effects being a maximumof quantity and quality production, and economy of mainte nance.

My improved alloy steel contains the following elements in about thepercentages stated, to wit:

Garbon 1.60 Chromium 2.25% Vanadium; 25% Iron 95.00% Silicon, manganese,&c .90%

Specification of Letters Patent. Pafientefi Jan, .3349, 1911 Applicationfiled October 31, 1916. Serial No. 128,696.

The minor elements silicon, manganese, sulfur, and phosphorus, may bepresent in the quantities incidentally found in ordinary steels; and thecontents of the stated essential elements may be varied within certainlimits without materially changing the essential characteristics of myimproved alloy steel: the carbon between 1.25 per cent. and 2.50 percent., the chromium between 1.50 per cent. and 2.50 per cent., with thevanadium remaining at approximately .25 per cent. or sufficient tosecure a hard homogeneous structure.

Rolls cast of this improved. alloy steel show, when cold, a scleroscopichardness of 55 to 65 about equal to that of chill rolls as commonlyemployed. This hardness, which extends through the homogeneous sectionalstructure, together with desired heat-resisting andshock-absorbingqualities, is imparted by the carbon, chromium, and vanadium elementscombined as stated, and a far stronger roll than the usual chill roll oflike diameter and length is produced; the yielding points for bothcompression and tension being so high as to insure great rigidity,though the elasticity is suflicient to insure against breakage underpossible undue strains. The hardness is such as to prevent objectionableWear, and is secured without liability to service cracks; so that amaximum length of service, as well as a maximum product output, isattained by employing my improved material in the manufacture of theserolls. 1

What I claim is:

The improved alloy roll-steel described, composed mainly of iron, withpercentages of carbon between 1.25 and 2.50, of chromium between 1.50and 3.00, and of vanadium approximately .25; the minor elements presentnot exceeding one per cent.

In testimony whereof I afiix my signature.

FRANK D. TAGGART.

